Rotary cutter for making expanded metal



Sept. 19, 1933.

R. M. CHESNEY 1,927,783

ROTARY CUTTER FOR MAKING EXPANDED METAL Filed June 19, 1929 2SheetsSheet l P 1933. R. M. CHESNEY 1,927,783

ROTARY CUTTER FOR MAKING EXPANDED METAL Filed June 19. 1929 E O O L "II"I IIII-% 2 Sheets-Sheet 2' Patented Sept. 19, 1933 I 1,927,783 7 sonnyCUTTER. FOR MAKING EXPANDED. Y METAL 1 Robert M. Ches ney, Warren, Ohio,assignon by mesne assignments, to United States Gypsum Company, IllinoisApplication J une 19,

Chicago, 'Ill., a corporation of 1929. Serial No. 372,165

Claims' (01. 164 -66) This invention relates to'improvements in rotarycutters and, more especially, rotary cutters iormaking expanded metal.

v r Cutters of the type to which my invention re- 0 lates are formedtoout rows of slits in the metal,

the slits in a rowbeing separated by bonds. The

slits of one row. are ordinarily staggered withv respecttothose of anadjacent row. Inorder to iorm the alternate slits and bonds of one row;

the cutters are provided with notches, it being understood that theunnotched portion of the cutter makes'the slit in the metal, the notchedportion not cutting the metal and, consequently, leaving the bond. I

In the use of the cutters, the cutting portions become dulled and mustbe sharpened. In,

the sharpening process, the diameter of the rotary cutter is.necessarily somewhat reduced. I-Ieretofore, it has beenthe practice tomake the notches on the cutters with parallel sides. The cuttingportions of the cutters were consequently substantially sector-shape.With such cutters, it will be seen that as the same are sharpened andthe diameter reduced, the notches remainthe same width while the cuttingportions be,- comev narrower due to their-sector. shape. Con.-sequently, such old type of cutters, when reduced in diameter, giveshorter slits in the, metal to be expanded. g

' .Theprincipal feature of. my invention is the making of a cutter thatwill continueto give slits of the same length (the length of the bondbeing reduced) as itis reduced in diameter by sharpening. This is ofconsiderable advantage "because if the length of the slit in the metalis reduced, the resulting expanded metal will be shortened. By the useof my invention, the completed expanded metal is not shortened as thediameter of the cutter is reduced. These features and the details of theinvention will be understood more fully as I proceed with myspecification. 7

In that form of device embodying the features of my invention shown inthe accompanying drawings- Figure 1 is a top plan view of a cutter; Fig.2 is a View taken as indicated by the line 2--2 of Fig. 1;- Figs. 3, 4,5 and 6 show the effect of reducing the length of slits in makingexpanded metal; Fig. '7 is an enlarged view of a portion of theperiphery of one of the cutters; and Fig. 8 is a view taken as indicatedby the line 8 of Fig. 7. 5 5 1 As shown in Fig. 1, the sheet metal beingslitted is indicated by 10, the slits therein being indicated by 11.Nui'neral 12 indicates the bondbetween two slits.

The slitting is accomplished by a plurality of pairs of rotary cutters,indicated, in general, by 13, 13, one operating above and one below themetal '10 in shearing relation, as shown in Fig. 2. The mechanism forrotating the cutters, for feeding themetal between the same, and thelike, form no part of the present inventionand need not be shown indetail here as these mechanisms are well known and understood in the,

art. Numeral 14 may indicate, in-general, a

shaft on which the rotary cutters 13, 13 are mounted.

A portion of the periphery of oneof the cutters is shown on anenlargedscale in Figs. '7 and p 8. As here shown, the cutting portions oftheperipheryor blades of the cutters are indicated For example, as shown inFig. '7, one blade 15 adapted to make one slit 11 in the metal extendsfrom the-point a to the point b. -It.is to be understood that there is'a(to-operating.

blade 15 on another cutter in shearing relation with the same. The endsof thecuttingv edge 15 are bounded by the notches 16, 16 inthe: cutter,said notches leaving the bonds 12 in the sheet metal; The side edges ofthe blade 15 areindicated by 1,5", 15' and it is to beparticularly-noted that these edges of, the blade '15 are parallel toeach other. This is the principalfeature of my invention. These paralleledges are carried up fto acircumference, as indicated by.1'l,.whichmaybe the grinding limit of the particular cutter shown. That is, thecutter may be reduced in diameter by grinding or sharpening until thecircumference 17 is reached without shortening the length of the slitsmade by the cutting edge e 15. If the sides 15', 15' of the blade'15were not parallel but substantially radial with respect the diameter ofthe'disk would result in shortening the length of the cutting edge' 15.

Making the terminal edges 15, 15' of one blade 15 substantially parallelresults in making thenotches 16 substantially sector shape, or taperedsomewhat from the periphery of the disk toward the center. That is, theadjacent edges 15 bounding one of the notches 16 are not parallel tereight inches in diameter may be reduced by to the disk, then it will beseen that reducing 9 sharpening to a diameter of seven and one-halfinches, or less. With the old type of cutter, this might result in areduction in length of the companded sheet. A loss of metal thusresults, and a further disadvantage lies in the weakeningof' the productif the degree of opening of the'slitsis increased too much.

The manner in which thefshortening of the length of the slit in the useof' cutters of. the

- prior art causes a reduction in the length of the completed metal maybe understood more clearly by reference to Figs. 3 to 6, inclusive. InFig.

3, one of the slits is indicated by 11 and thebonds by 12*. This pieceof metal is shown expandedin Fig. 4. It is to be understood that thetransverse expansion distance, as indicated by 18, is constant; As shownin Fig. 4, when the metalis expanded, the slit 11 is opened-up asindicated. The transverse expansion 18 given tothestrip causes a certainamount of contraction in the length'of the same, depending upon thelength of'the slit 11 For example, with a strip as shown in Fig. 5wherethe slits 11 are shorter than those indicated by 11 and wherethetransverse expansion, as indicated by 18' is the same as indicated by18 in Fig; 4, the longitudinal contraction of the piece of metal issomewhat more. I

For example, the longitudinal distance after a contraction-using thelong slit is indicated by 19 in Fig. 4. With the shorter slit, thisdistance is indicated byl9' in Fig. 6 and it willbe-seen,

that 19' is shorter than 19. It will be seen, therefore, that commencingwith'two pieces of.metal of Tthe same length and width, and providingone with long slits and the other with short slits,

and-expanding each one to the samewidth, the

one with the long slits will be longer after completion.:tha'n the onewith the short slits.

According to the preferred. form of the present invention, the length ofthe slits is held constanthowever much the cutter is ground'down,'so-that' the above-mentioned disadvantages of loss-ofmetal andweakeningof'the product areeliminated. It will be understood that the actualshortening of' the bonds as the cutter is ground down isso slight as tobe inconsequential, the imtion to claim all novelty inherent in myinvenportant factor being the avoidance of undue shortening of theslits.

While I have shown and described certain embodiments of my invention, itis to be understoodthat it is capable of many. modifications.Changes,.therefore,' in the constructiomand arrangement maybe madewithout departing from thespirit' and scope of the invention asdisclosed inthe appended claims, in which'it is myinten tionas broadlyas possible, in view of the prior art. What I regard as new, and desireto secure by Letters Patent, is:.

1. A rotary cuttercomprising a disc for forming spaced 'slitsin metal tobe expanded, one wall of said disc being'provided with uniformly spacednotches intercepting the peripheral cutting edge of saiddisc,said'not'ches flaring toward the periphery of the disc whereby thelength of slits produced by the cutter will not be shortened as thecutter wears-down:

2. A rotary cutter comprising a'disc for form'-- ing spaced slits inmetal to be expanded;said disc' being i provided withsector-shaped'notches intercepting the peripheral'cutting edge ofsaid-disc; said notches forming individual cutting'blads withsubstantially parallel sides extending inward'ly into saidcutter, sothat the'le-ngth'of 'slitsin the metal-producedby said blades,willremain 105 constant as said cutter isreduced in-diameterbecause ofWear. i

3.1A metal lath slitting disk having: radial notches ina side-thereofopening-'through-"th'e" outer edge of the disk, said notches being- 0f:pro=- no gressively' decreasing: width toward the'" centerof"thei'disk'. I

4; A metal I lath slitting disk having elongated 5 tapered notchesequally spaced along the pe riphery at'the sides, the notches onoppo'si-tesidesibeing in staggered relation; the bases of the" notches.being in the circumference," and the apices'of the notches beingtoward-thecenter;

5. A rotary cutter-'comprising-a discfonform' ing spaced slits in metalto" be expanded," wall of said disc being-provided with uniformlyspacednotches" intercepting" the peripheral cut ting edge of said disc, saidnotches being-.wid'er at' the periphery: of said disc' than at pointscl'oser to the center of said disc, whereby the bonds be' tween theslits produced by the cutter will be shortened a s'the diameter of'thefcutter is de-

